[PATCH] ppc64: suppress 'store_purr' unused warning

Some new sysfs macros declare a store_purr() function that never gets used,
which makes a compiler warning happen.  Suppress the warning with the used
attribute.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/ppc64/kernel/sysfs.c

@@ -208,8 +208,8 @@ static ssize_t show_##NAME(struct sys_device *dev, char *buf) \
 	unsigned long val = run_on_cpu(cpu->sysdev.id, read_##NAME, 0); \
 	return sprintf(buf, "%lx\n", val); \
 } \
-static ssize_t store_##NAME(struct sys_device *dev, const char *buf, \
-			    size_t count) \
+static ssize_t __attribute_used__ \
+	store_##NAME(struct sys_device *dev, const char *buf, size_t count) \
 { \
 	struct cpu *cpu = container_of(dev, struct cpu, sysdev); \
 	unsigned long val; \